decodeFunctionData
Decodes ABI encoded data (4 byte selector & arguments) into a function name and arguments.
The opposite of encodeFunctionData.
Install
ts
import { decodeFunctionData } from 'viem'
Usage
Below is a very basic example of how to encode a function to calldata.
ts
import { decodeFunctionData } from 'viem'
const { functionName } = decodeFunctionData({
abi: wagmiAbi,
data: '0xc2985578'
})
// { functionName: 'totalSupply' }
ts
export const wagmiAbi = [
...
{
inputs: [],
name: "totalSupply",
outputs: [{ name: "", type: "uint256" }],
stateMutability: "view",
type: "function",
},
...
] as const;
ts
import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'
export const publicClient = createPublicClient({
chain: mainnet,
transport: http()
})
Extracting Arguments
If your calldata includes argument(s) after the 4byte function signature, you can extract them with the args return value.
ts
import { decodeFunctionData } from 'viem'
import { publicClient } from './client'
import { wagmiAbi } from './abi'
const { functionName, args } = decodeFunctionData({
abi: wagmiAbi,
data: '0x0423a1320000000000000000000000000000000000000000000000000000000000000001'
})
// { functionName: 'balanceOf', args: [1n] }
ts
export const wagmiAbi = [
...
{
inputs: [{ name: "owner", type: "address" }],
name: "balanceOf",
outputs: [{ name: "", type: "uint256" }],
stateMutability: "view",
type: "function",
},
...
] as const;
ts
import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'
export const publicClient = createPublicClient({
chain: mainnet,
transport: http()
})
Return Value
ts
{
functionName: string;
args: unknown[] | undefined;
}
Decoded ABI function data.
functionName
- Type:
string
The decoded function name.
args
- Type:
unknown[] | undefined
The decoded function arguments.
Parameters
abi
- Type:
Abi
The contract's ABI.
ts
const { functionName } = decodeFunctionData({
abi: wagmiAbi,
data: '0xc2985578'
})
data
- Type:
Hex
The encoded calldata.
ts
const { functionName } = decodeFunctionData({
abi: wagmiAbi,
data: '0xc2985578'
})